Apparatus for maintaining pressure in fuel-oil tanks of submarines



F. KRAMER.

APPARATUS FOR MAINTAINING PRESSURE IN FUEL OIL TANKS 0F SUBMARINES:

APPLICATION FILED AUG.3I| 1921.-

1 112,357. Patented Apr. 11, 1922.

IumEGw 7 1 PATENT OFFICE.

FRITZ KRAMER, OF BLANKENESE:DOCKENII'UDEN, .NEAR HAMBURG, GERMA. Y.

APPARATUS FOR MAINTAINING IN FUEIrOIL TANKS O1 SUBMARINES.

Application filed August 31, 1921.

Specification of letters Patent.

Patented Apr. 11, 1922.

Serial No. 497,283.

(GRANTED UNDER THE PEOVISIQNS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

To aZZ whom it may concern:

Be it known that I, FRITZ KRAMER, a cit zen ofthe Republic of Germany, and a resident of Blankenese Dockenhuden, near Hamburg, Germany, haveinvented certain new and useful Improvements in A paratus for Maintaining Pressure in Fuel-Gil Tanks of Submarines, (for which I have-fil d application in Germany Aug. 2, 1918, issued Sept. 22, 1920,- Patent No. 326,026,) of which. the following is a specification.

The fuel-oil containers of submarines are commonly disposed outside of the main hull and with walls which are not designed to sustain any very great pressure difference on opposite sides. It is difiicult to build and maintain such wall absolutely tight but leakage of oil from the tank is objectionable because it serves to indicate the loca tion of the submarine w ien submerged, and because of oil cost.

This invention is an apparatus by means of which a sub-pressure can. be built up and maintained in the fuel-oil containers for the purpose of preventing outward leakage of the fuel-oil.

Bearing the resisting strength'of the tanks in mind, it is necessary to make such por vision as will assure that, on the submersion of the boat, the pressure caused by the seal on the outside of the tank wall will nearly if not quite be reached by the pressure on the interior of thetank wall.

In order to make sure that when the boat is submerged, no oil will pass out through the. tank walls, which in present existing constructions leak to a limited degree, it is important to keep, at all times, the pressure within the tanks not above that on the outside. The problem consists of maintaining as nearly as possible, for every position and movement of the boat under water a certam counter-pressure in the tanks equal to or slightly below the pressure exerted by the surrounding sea.

The desired sub-pressure in the fuel-oil tanks during submersion may be taken care of to a certain degree by the pressure difference caused by the friction of the flow of the sea-water through the system of seapiping, but this seapiping is made large to take care of the rapid change in pressure resulting from quick submersion and therefore offers very little friction and causes very little. pressure dilterence.

The resistance of the piping-system can be easily increased in and made adjustable as for instance by the, installation of a weighted valve. If the usual resistance of the pipe system is low compared to that of the valve then the valve will maintain a certain dilierence of pressure between the sea and the container, as long as the flow takes place from the sea toward the tank as in diving, but on rising the friction of the piping systems operates in the reverse sense as the flow now occurs from the tank to the sea, and it tends to produce a small overpressure in the tank.

A subpressure when the boat is rising, may be secured by the use of a pump, and the load imposed on the pump is determined by tlie speed of the rising.

By means of this invention it is possible to satisfy the various needs above referred to, by an apparatus of the greatest simplicity possible, with lightness of weight, small space requirement, and smallest power consumption.

The invention in its preferred form consists of an arrangement whereby as soon as the boat is under water, a very small leakage pump is run to continuously draw from the tank and feed towards the sea, so that by the operation of this pump a flow line between the tank and the sea is-established. Two valves are so installed in by-passes around the pump that when a flow occurs "from the seal towards the storage-tank a constant sub-pressure is maintained in the tank for all pressures oi the sea, and when the reverse happens and a flow exceeding the capacity of the pump occurs from the storage tank to the sea the smallest possible overpressure is produced.

The accompanying drawing shows one form which may be employed for the invention, the view being a sectional one.

lis a valve chamber with a connection 2 with the sea and a connection 3 with the fuel-oil tank. The chambers 2 and 3 are separated from each other by two valves 4: and 5 and connected to each other by passages 6 and. 9 between which the pump 7 is located. The space 2 connects with the sea and the space 3 connects with the 9. falls.

portion of the oil-tank in which the inleaking sea water separates from the oil and collects by the difference in gravity of the two. Y

The pump which may be a gear pump or a centrifugal one, is driven by motor 8 and draws from space 3 and discharges into space 2. Valve 5 opens toward the tank and is loaded by a spring or in any suitable manner as for instance, with such weight as to insure its acting only when a predetermined excess of pressure occurs in space 2 over that in space 3. The loading is such that the throttling down of the water passing into the tank produces the desired subpressure in the tank.

Independent of the valve 5 is a returnflow valve 4 which is made as light as possible and-so disposed that an over-pressure from space 2 towards space 3 will seat it and keep it closed but that the slightest over-pressure from space 3 towards space 2 will open it. The areas of spaces 2 and 3 as well as those 01 valves at and 5 are of generous dimensions so as to permit rapid flow in case of need. On the cont ary the passages 6 and 9 as well as the capacity'ot' the pump are only for a very limited water flow, that is such as is considered the normal leakage of the storage tanks.

The operation is as follows: As soon as the boat dives the pump is started and runs continuously. It now pumps out to the sea such water as may normally pass due to leakage of the tank walls and thus maintains in the fuel-oil tanks the desired sub-pressure. This sub-pressure corresponds to the loading of valve 5 which opens and allows the return of a part of the water fed by the pump when the latter creates too great a sub-pressure.

If the boat goes still deeper then the pressure in space 2 increases and lifts valve 5 further allowing more water to flow from the sea to the tank. Thus valve 5 continues to maintain the desired constant difference or" pressure.

lVhen the boat rises the pressure in space Valve 5 closes and valve 4- remains closed as long as the pump can maintain a sub-pressure by delivering water from the tank towards the sea. lVhen this is not possible, for example when theboat rises so rapidly that the compressible gases in the tank can not expand quickly enough, then the valve 4; opensand prevents any superpressure in the tank.

The particular advantages of the described arrangement are that the pump and motor can be of small dimension and that their load is small, furthermore that under all normal circumstances a certain sub-pressure is maintained in the fuel-oil tanks while under unusual circumstances no noteworthy super-pressure can develop.

Having thus described the invention what I claim is:

1. An apparatus for maintaining a subpressure in the fuel-oil tanks of submarine boats including a weighted inwardly opening valve, a non-loaded outwardly opening valve and an outwardly delivering pump operable independent of each other, whereby upon decreasing tank pressure a flow from the sea towards the tank occurs by the weighted valve, and upon rising tank pressure, a flow is started from the tank towards the sea through pump and by a still greater increase of tank pressure the outflow occurs also through the second mentioned valve.

2. An apparatus for controlling the pressure of outboard oil tanks of submarines and preventing the leakage of oil therefrom including a pump of small capacity and acting to'draw inleaking water from the tank and normally maintaining a pressure. in the tank below that of the surrounding sea and means for establishing communica tion between the tank and the sea independently of the pump in case of slight superpressure or more than a predetermined subpressure in the tank.

3. An apparatus for controlling the pressure of outboard oil tanks: of submarines and preventing the leakage of oil therefrom including a pump of small capacity and acting to draw inleaking water from the tank and normally maintaining a pressure in the tank below that of the surrounding sea, valve mechanism opening upon slight super-pres sure or more than a predetermined sub pressure in the tank and permitting flow independently of the action of the pump.

a. An apparatus for controlling the pressure of outboard oil tanks of submarines and preventing the leakage of oil therefrom including a pump of small capacity and acting to draw inleaking water from the tank and normally maintaining a pressure in the tank below that of the 'surrounding sea, and by-passes around the pump, one including a non-loaded outwardly openin valve and the other a loaded inwardly openin valve. 7

Signed at 'l lamburg, Germany, this 6th. day of August, A. I). 1921.

FRITZ KRAMER. 

